Today we can release benefits of radio thanks to such important inventions as the telegraph and telephone being close and interconnected. When the electromagnetic waves were discovered the scientists invent the method to transmit information through the air. Before the radio technology were known as wireless telegraphy. Now this capacity is still in great demand meeting the needs of people in entertainment and information. There are thousands of stations broadcasting various radio channels throughout the world.
Step by Step
- This exciting journey started in 1895 when Guglielmo Marconi was able to send and receive the first radio signal within the territory of Italy. In four years the distance become larger – a wireless signal was sent across the English Channel. In another three years Marconi managed to send the signal in the form of the letter “S” from England to Newfoundland – a short message but very important. At the same time Nikola Tesla patented the radio transmitters operating without wire. This is Nikola Tesla who is usually mentioned as an inventor of radio technology.
- Then the events came thick and fast. While Tesla and Marconi sent the letters by wireless method Reginald Fessenden from Canada managed to transmit the first voice message and that happened in 1900. He made the first radio broadcast at the end of 1906.
- Soon the complete speech was transmitted across the continents. It happened in 1915.
- The radio began penetrating with other industries and in 1930 a car radio was intended by Motorola.
- Later in 1933 Edwin Armstrong defined the principles of frequency modulation making the audio signal much better decreasing the noises produced by equipment and the earth’s atmosphere. Here we got FM radio that is popular up to now.
- And of course we cannot omit reference of Satellite radio. This story started in 1992 when four companies in the world got the license to broadcast within satellite-based Digital Audio Radio Service.
What is the Principles of Radio Waves?
So today you can drive down the road in a car feeling happy, turn on the radio, tune it to any station you want and enjoy sounds or information of any kind. It is so simple, isn’t it? But how does it work?
There is electromagnetic radiation, which is produced by electric or magnetic field of the Earth and has different length. Both these fields exist in waves, which are perpendicular to each other. The type of EM radiation with the longest wavelength is radio waves, which are used by radio stations for transmitting the sound in an encoded form or as specialists say: being modulated. This encoded or modulated information is broadcasted on a certain frequency picked up by an antenna of a transmitter and decoded by it offering as a sound.
In general the quality of radio reception depends on many different things like type of modulation, the power of station, geographical location and so on. There is always room for perfection. Perhaps you are able to make the world better and invent the way to exclude those factors influencing on perfect radio sound.
Influence of Radio Waves on Human Health
The scientists insist that there are no adverse effects of radio waves, but still there are questions as to their impact on our health. A lot of researches were conducted to find the biological effects of radio waves or to prove their complete safety. All of them show that the clearest and most studied effect of electromagnetic fields is capability to heat. In other words, if you stand near antenna of working high-power transmitter, you will feel warmness and if you touch it, you can get even a burn. The principle is the same as with a microwave oven.
There are no other defined and proved dangers but the precautions are recommended. The radio waves may cause slight headaches, sleep disorders, other neurological problems, so you’d better keep it away from bedroom and children’s room. But this opinion has not official grounds.